Pokemon crater is a MMORPG (massive multiplayer online role playing game) involving pokemon.
Pokemon crater is played online, rather than on a console, which allows players to interact, battle and trade pokemon with each other. The idea of the game is to catch pokemon, increase their strength, and battle them against other pokemon. Pokemon battle against each other in a turn-based fashion, in which the player selects an attack each turn to use on the opponent. A pokemon used to fight against another pokemon gains experience. Once a certain amount of experience is obtained, the pokemon levels up, which allows new attacks to be used and improves old ones. Furthermore, when some pokemon reach a certain level, they can evolve into a improved pokemon. For instance, once a croconaw reaches level 30, it can evolve into a feraligatr.
gym leaders are computer-controlled opponents who have a certain type of pokemon, for instance rock or grass. Players can battle gym leaders in the same way they battle regular players. The only difference is that, if the player defeats the gym leader, they recieve a badge, which goes onto their profile to show what gym leaders they have defeated.